On my Nuvi you can't program the size of the RV. I downloaded the avoidances and alerts. The low clearances was a set I paid for and they work very well. Most of the other things, campgrounds, Walmarts, etc., can be downloaded for free from POI Factory.
I use the Nuvi with the routes that I program. That way I know where I'm supposed to go, and hopefully there will be no surprises. The Nuvi 465 had optional truck routing, so it would route you around "No Truck" routes, even if you were using them as your pre-programmed route. Very, very annoying. I usually used the Automotive selection to avoid those issues.
I have the 5" screen because I felt the 7" screen was just too large and intrusive. I mainly listen to it and only occasionally glance at it.
